Jody Wilson-Raybould says she faced “consistent and sustained” political pressure from Prime Minister Justin Trudeau and top officials, including “veiled threats,” on the need to shelve the criminal prosecution of Montreal’s SNC-Lavalin Group Inc.

In dramatic televised testimony before the House of Commons justice committee spanning 3½ hours, the former justice minister and attorney-general outlined detailed conversations at the highest levels of the Trudeau government about helping the Quebec engineering and construction giant out of its legal difficulties.

Ms. Wilson-Raybould said the intense, behind-the-scenes campaign to press her to intervene in the justice system involved about 10 phone calls and 10 meetings that she characterized as inappropriate between September and December, 2018.

“I experienced a consistent and sustained effort by many people within the government to seek to politically interfere in the exercise of prosecutorial discretion in my role as the attorney-general of Canada in an inappropriate effort to secure a deferred prosecution agreement with SNC-Lavalin,” Ms. Wilson-Raybould told MPs.

Conservative Leader Andrew Scheer later called on Mr. Trudeau to resign, saying he has “lost the moral authority to govern,” and said the RCMP should investigate. NDP Leader Jagmeet Singh called for a public inquiry.

Mr. Trudeau told a late news conference in Montreal that neither he nor his staff acted inappropriately and that he has faith in an investigation by the Ethics Commissioner.

“I therefore completely disagree with the former attorney-general’s characterization of events,” he said.

Asked if he would resign, he said Canadians will have a choice this fall to pick which party should lead the country.

He said he would review Ms. Wilson-Raybould’s testimony before deciding whether she will remain in the Liberal caucus.

Ms. Wilson-Raybould alleged inappropriate conduct on the part of Mr. Trudeau and 11 people in the Prime Minister’s Office, the Privy Council Office and the Office of the Minister of Finance, including Mr. Trudeau’s chief of staff, Katie Telford, and principal secretary Gerald Butts, as well as Clerk of the Privy Council Michael Wernick, Finance Minister Bill Morneau, and his chief of staff, Ben Chin.

“Within these conversations, there were express statements regarding the necessity for interference in the SNC-Lavalin matter, the potential for consequences and veiled threats if a DPA [deferred prosecution agreement] was not made available to SNC,” she said.

Ms. Wilson-Raybould said Mr. Trudeau and other senior officials pressed her to overrule the director of the Public Prosecution Service of Canada, Kathleen Roussel, and negotiate an out-of-court settlement with SNC-Lavalin – a move that they said would also help the Quebec Liberal Party in last fall’s provincial election.

“After I had made my decision as the attorney-general not to issue a directive, the successive and sustained comments around jobs became inappropriate because I had made my decision and everybody was fully aware that I had made my decision,” she said in response to questions from MPs. “The Quebec election, any partisan considerations before or after, are entirely inappropriate, not relevant to me at the time wearing my judicial hat as the attorney-general.”

SNC-Lavalin faces one charge of corruption under the Corruption of Foreign Public Officials Act and one charge of fraud under the Criminal Code. It is alleged SNC paid millions of dollars in bribes to public officials in Libya between 2001 and 2011 to secure government contracts.

The engineering company says executives who were responsible for the wrongdoing have left the company, and it has reformed ethics and compliance rules.

If convicted, SNC-Lavalin could be banned from bidding on federal contracts for up to 10 years.

The company had been lobbying officials in Ottawa to secure a settlement, under which it would accept responsibility, pay a financial penalty, relinquish benefits gained from the wrongdoing and put in place compliance measures.

In a meeting on Sept. 17 last fall that included Ms. Wilson-Raybould and Mr. Wernick, the Prime Minister said he wanted a solution to SNC-Lavalin’s legal troubles, the former attorney-general said.

“The Prime Minister asked me to help out, to find a solution to SNC, citing that if there was no DPA, there would be many jobs lost and that SNC would move from Montreal,” she said. “In response, I explained to him the law … and I told him that I had done my due diligence and made up my mind on SNC and that I was not going to interfere with the decision of the DPP [director of public prosecutions].”

Ms. Wilson-Raybould said the Prime Minister once again cited the potential loss of jobs and then “to my surprise, the clerk started to make the case for the need to have a DPA” in which he noted SNC had a board meeting on Sept. 20 with stockholders and might move its headquarters from Montreal to Britain.

Mr. Trudeau even cited his own political base in Quebec.

“At that point the Prime Minister jumped in stressing that there is an election in Quebec and that ‘I am an MP in Quebec — the member for Papineau,’” she recalled.

“I was quite taken aback. My response – and I remember this vividly – was to ask the Prime Minister a direct question while looking him in the eye. I asked: ‘Are you politically interfering with my role, my decision as the attorney-general? I would strongly advise against it,’” Ms. Wilson-Raybould said.

She said the Prime Minister replied: “‘No, no, no, we just need to find a solution.’”

Ms. Wilson-Raybould said Mr. Butts told her in a Dec. 5 meeting that the PMO did not like the independent public prosecution service, noting Stephen Harper’s Conservative government created it.

On Dec. 18, Ms Wilson-Raybould said her chief of staff, Jessica Prince, who took notes, was summoned to a meeting with Mr. Butts and Ms. Telford. They wanted an external legal opinion obtained to review the director of prosecutions’ decision.

Ms. Prince told the pair this would constitute interference, Ms. Wilson-Raybould said, citing notes she took after her chief of staff recounted the conversation to her.

At this meeting, according to Ms. Wilson-Raybound, Mr. Butts replied: “’Jess, there is no solution here that doesn’t involve some interference,’” while Ms. Telford said: “We don’t want to debate legalities any more.”

The former Liberal minister also had a different account of a Dec. 19 meeting with Mr. Wernick during which Ottawa’s top bureaucrat made it clear the Prime Minister was not happy with her intransigence. The privy council clerk last week said he was simply providing context for Ms. Wilson-Raybould.

But the B.C. MP said she told him this meeting brought to mind the Saturday Night massacre, she said – recalling the firing of the attorney-general during U.S. president Richard Nixon’s Watergate scandal.

During this meeting, Mr. Wernick said Mr. Trudeau was insistent on a deferred prosecution.

“The clerk said that the Prime Minister is quite determined, quite firm but he wants to know why the DPA route which Parliament provided for isn’t being used,” she recalled. He said, “I think he is gonna find a way to get it done one way or another. So, he is in that kinda mood and I wanted you to be aware of that.”

Ms. Wilson-Raybould said she believed she was demoted to veterans affairs because she would not do what the Prime Minister wanted to help SNC-Lavalin.

The Prime Minister called her on Jan. 7 to tell her she was being moved out of the Justice portfolio, she recalled.

“I will say that I stated I believed the reason was because of the SNC matter. They denied this.”

Ms. Wilson-Raybould said she would have “resigned immediately” from cabinet if new Justice Minister David Lametti had ordered a negotiated settlement with SNC-Lavalin.

Wednesday was the first time Ms. Wilson-Raybould has spoken about what happened.

Since The Globe and Mail first reported the story, Ms. Wilson-Raybould has resigned from cabinet and Mr. Butts stepped down as Mr. Trudeau’s principal secretary. Ethics commissioner Mario Dion has launched an inquiry.

In the political fallout, the Prime Minister bowed to Ms. Wilson-Raybould’s request to waive solicitor-client privilege and cabinet confidentiality to testify before the committee.

However, she said she was still not at liberty to reveal the nature of conversations with the Prime Minister after she was shuffled to Veterans Affairs in January, adding she feels there is relevant information that she is still unable to share with Canadians.

The Prime Minister and Mr. Wernick have denied Ms. Wilson-Raybould was subjected to “inappropriate pressure” with the clerk calling the conversations with the attorney-general “lawful advocacy.”

In her 22-page opening statement, Ms. Wilson-Raybould recounted the meetings and conversations that took place last fall that began two days after Ms. Roussel informed SNC-Lavalin on Sept. 4 that she intended to proceed with a criminal prosecution of SNC-Lavalin.

Two days later, Mr. Chin, the finance minister’s top aide, e-mailed Ms. Prince to say if SNC-Lavalin did not get a deferred prosecution “they will leave Montreal, and it’s the Quebec election now – so we can’t have that happen,” she recalled for MPs. Mr. Morneau also discussed the issue with her on Sept 19.

Mr. Morneau’s office defended the actions of the minister and his chief of staff in a statement on Wednesday evening.

“It is Minister Morneau’s responsibility to protect and promote the creation of jobs across Canada and he will continue to raise such important issues with all his cabinet colleagues,” said the minister’s spokesperson, Pierre-Olivier Herbert. “At no time did Minister Morneau nor members of his office pressure the former minister of justice and attorney-general into making any decision regarding the prosecution of SNC Lavalin.”

The day before the Sept. 17 meeting, Ms. Wilson-Raybould said Ms. Prince had a phone call with two of Mr. Trudeau’s top advisers – Mathieu Bouchard and Elder Marques – to complain that the individual Crown prosecutor on the case wanted to cut a deal with SNC-Lavalin but Ms. Roussel would not go along.

The Globe and Mail reported on Feb. 7 that the PMO wanted Ms. Wilson-Raybould to get outside legal advice on allowing a deferred prosecution – a proposal she rejected.

“The consistent and enduring efforts, even in the face of judicial proceedings on the same matter – and in the face of a clear decision of the director of public prosecutions and the attorney-general – to continue and even intensify such efforts raises serious red flags in my view,” the former minister told MPs.

“Yet, this is what continued to happen,” she said. “In my view, the communications and efforts to change my mind on this matter should have stopped.”

NDP MP Murray Rankin praised Ms. Wilson-Raybould for speaking out.

“What I heard today, should make all Canadians extremely upset. There is no other conclusion that one can reasonably draw but there was a sustained, consistent effort to interfere politically with the critical role that an attorney-general must play in our legal system,” Mr. Rankin said.